Development of Orbital Magnetic Quantum Number Measurement Method and Application to the Investigation of Low-dimensional Electronic Properties

2020 Fiscal Year Final Research Report

• Project/Area Number: 17H02911
• Research Category: Grant-in-Aid for Scientific Research (B)
• Allocation Type: Single-year Grants
• Section: 一般
• Research Field: Condensed matter physics I
• Research Institution: Institute for Molecular Science
• Principal Investigator: Matsui Fumihiko 分子科学研究所, 極端紫外光研究施設, 主任研究員 (60324977)
• Project Period (FY): 2017-04-01 – 2021-03-31
• Keywords: 光電子回折 / 軌道角運動量 / 電子状態

Outline of Final Research Achievements

Element and atomic-site selective information on the electronic structure can be obtained from the photoelectron diffraction (PD). We have developed methods and analyzers for measuring orbital magnetic quantum numbers from PD circular dichroism. We discovered that circular dichroism also appears in the resonant Auger electron diffraction at the L-shell absorption edge. This effect (2-hole generation) is significant in 3d transition metals, especially in late transition metals from Cu to Fe. On the contrary, in the early transition metal compounds such as TiO2, the resonance photoelectron emission of 1-hole generation became dominant, and it was shown that the specific band dispersion was emphasized and observed elementally. Furthermore, we studied the resonance process at the K-shell absorption edge of light elements, and found a resonance Auger transition process in graphite, in which the total momentum of two electrons is conserved, which is different from ordinary photoelectrons.

Free Research Field

表面物理、放射光科学

Academic Significance and Societal Importance of the Research Achievements

軌道磁気量子数は局所的な電子運動の対称性と結びつき、様々な電子物性の発現と密接な関係にあるが、こうした軌道磁気量子数を直接計測する手段がこれまでなかった。本研究では当初想定した銅や鉄などの共鳴オージェ電子回折に加え、前期遷移元素や軽元素に対象を広げ、光励起過程の基礎を明らかにし、一連の研究を盛り込んだ教科書「光電子分光詳論」を出版した。
広角取り込み分析器に加え、全角度分布計測を可能にする全天球光電子取り込み電場レンズ、直角偏向イメージングでスピン量子数の垂直成分の解析の道を拓く分析器の考案を行い、それぞれ特許出願にこぎつけた。計測手法考案・新装置開発・基礎学理開拓を通じて基礎科学に貢献する。